The prediction of tsunami travel time to Mataram City Indonesia based on North Lombok earthquake as the initial condition

The area is close to Mataram City, the capital of West Nusa Tenggara Province, and a major tourist destination. The assessment of tsunami hazard is crucial due to the densely populated area, with a total population of 459,314 persons in 2016 and an average population density of 7,493 persons per square kilometer. The tsunami simulation was conducted using the COMCOT Model, which is based on the North Lombok earthquake as the initial condition. The simulation result shows the prediction of tsunami travel time to be about 18 ~ 20 minutes from the source location to Mataram City. The height of the tsunami wave is 0.13 ~ 0.20 meters due to the earthquake magnitude of about 6 Mw. The simulation was performed to examine the tsunami occurrence of the four biggest earthquakes in the area, with the May 30th, 1979 event chosen due to its biggest magnitude (6.4 Mw) and shallower depth (25 km). The earthquake data and fault mechanism were taken from the USGS, and the rupture parameters were calculated using Wells & Coppersmith's method. The Okada's method was applied to compute the sea surface displacement, which is based on rupture parameters. The numerical simulation of tsunami propagation was performed using the Cornell Multi-grid Coupled Tsunami Model (COMCOT), which is an open-source program that applies the long-wave equation or shallow water equation for simulating the propagation of tsunami from the source until coastal area. The bathymetry data was taken from the General Bathymetric Chart of the Oceans (GEBCO), and the data were used as a numerical grid mesh covering the area from 7.2° to 8.9° S latitude and 115.2° to 116.4° E longitude. The mesh size is 30 seconds (about 928 m) in both directions. The simulation result shows the tsunami wave propagation in 0, 5, 10, and 15 minutes, with the wave height increasing as it approaches the coastal area. The results of the simulation show that the tsunami wave will reach Mataram City in about 18 ~ 20 minutes, with a wave height of 0.13 ~ 0.20 meters. The simulation was performed to examine the tsunami occurrence of the four biggest earthquakes in the area, and the results show that the May 30th, 1979 event has the highest potential for tsunami occurrence due to its biggest magnitude (6.4 Mw) and shallower depth (25 km).